How to acces all objects via Python in the Game Engine?
You can access all objects from the scene by its name:

import GameLogic
scene = GameLogic.getCurrentScene()
obj=scene.objects['ObjectName']


To access the vertices:

import GameLogic


scene = GameLogic.getCurrentScene()
obj=scene.objects['Cube']

mesh = obj.meshes[0]

for v in range(mesh.getVertexArrayLength(0)):
    vert = mesh.getVertex(0, v)
    print( "%d,%d,%d" % ( vert.x, vert.y, vert.z ))

print( dir( vert ))